An infrared study of the eclipsing dwarf nova U Geminorum

Open Access
Publisher Website
Google Scholar
Abstract
We present broadband infrared photometry (J, H, K) of the cataclysmic binary system U Geminorum throughout two orbital cycles; one series of data was obtained several days before an outburst, and a second series when the system had returned almost to quiescence from the same outburst. In quiescence, the red star, an M4–M5.5 dwarf, supplies most of the infrared luminosity of the system. The quiescent light curves, which are doubly sinusoidal with a peak-to-peak amplitude of 0.22 mag, are the tidally induced ellipsoidal variations of the red dwarf. The amplitude of the light curves is such that the red dwarf must fill, or nearly fill, its Roche lobe and shows directly that Roche lobe overflow is important in cataclysmic variable stars. The disc is brighter after outburst. Its infrared colours can lie in the range J–H = 0.3 to 0.8 and H–K = 0.3 to 0.7. These colours suggest that cool, optically thick gas (T ≼ 2500–3000 K) and optically thin gas supply most of the infrared light of the disc.

This publication has 0 references indexed in Scilit: